The present invention relates generally to chucks for use with drills or with electric or pneumatic power drivers. More particularly, the present invention relates to a chuck of the keyless type which may be tightened or loosened by hand or by actuation of the driver motor.
Both hand and electric or pneumatic tool drivers are well known. Although twist drills are the most common tools used with such drivers, the tools may also comprise screw drivers, nut drivers, burrs, mounted grinding stones, and other cutting or abrading tools. Since the tools may have shanks of varying diameter or may have a polygonal cross section, the device is usually provided with a chuck that is adjustable over a relatively wide range. The chuck may be attached to the driver by a threaded or tapered bore.
A wide variety of chucks have been developed in the art. In one form of chuck, three jaws spaced circumferentially approximately 120° apart from each other are constrained by angularly disposed passageways in a body attached to the drive shaft. The chuck is configured so that rotation of the body in one direction with respect to a constrained nut forces the jaws into or away from the gripping relationship with a tool shank. Such a chuck may be keyless if it can be tightened or loosened by manual rotation. Examples of such chucks are disclosed in U.S. Pat. Nos. 5,125,673 and 5,193,824, commonly assigned to the present assignee and the entire disclosures of which are incorporated by reference herein. Various configurations of keyless chucks are known in the art and are desirable for variety of applications.
Various quick change chuck devices are known in the art. One exemplary such device includes a body with a central bore that receives a bit having a polygonal cross-section. The body includes a groove extending transversely across the body and opening into the axial bore. The bit includes an annular groove at its rear end. A wire is disposed in the body groove so that when the bit is pushed into the bore, the bit pushes the wire radially outward. The wire is, however, biased radially inward. Thus, when the groove at the bit's rear end aligns with the wire, the wire moves into the bit groove to positively retain the bit in the chuck bore.
The chuck body includes a stem portion extending from its rear. The stem may be received in the bore of a three-jawed oblique chuck as described above so that the quick-change chuck is secured to the drill by the three-jawed chuck. Another quick-change device is disclosed in U.S. Pat. No. 5,947,484, the disclosure of which is incorporated by reference herein.